38
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Maintenance and service
C 1210 ES/ESC
6 720 644 887 (2013/02)
C. Adjusting CO
2
:
Note
:
P1 adjustment will change the P2 reading. Confirm the P1
value BEFORE adjusting the P2 level.
1. If P1 CO
2
level is off:
▶ Loosen yellow painted Phillips screw (1) and cover should rotate
down (2) revealing a recessed brass slotted screw. Fig.69.
▶ Turning the slotted screw counter clockwise will raise P1 CO
2
levels
and clockwise will lower P1 CO
2
levels. Adjustments to the slotted
screw will also change P2 CO
2
levels.
▶ After bringing the P1 CO2 readings in proper range, press the
button to enter the P2 mode. Verify CO
2
readings in P2 mode.
2. If P2 CO
2
level is off:
▶ Remove yellow painted #40 Torx cover from the front of the gas valve.
(Fig.70) A plastic #40 Torx screw will be revealed.
▶ Turning the plastic #40 Torx screw counter clockwise will lower P2
CO
2
levels and clockwise will raise P2 CO
2
levels.
Note
: This screw adjustment is very sensitive and should be made in
small increments. It may take several minutes for readings to stabilize.
3. Verify both P1 and P2 CO
2
readings are within the ranges specified in
table33. Repeat steps 1 and 2 as necessary until CO
2
values are within
the specified ranges.
Final Readings
P1 CO
2
Reading:
% CO
2
P2 CO
2
Reading:
% CO
2
D. Returning to Service:
1. Return slotted screw cover to original position.
2. Reinstall Torx cover.
3. Remove CO
2
analyzer probe and reinstall flathead screw with gasket
in exhaust collar.
4. Press ON/OFF button to turn OFF the heater and then turn ON the
heater.
5. Heater is ready for normal operation.
Fig. 69 Adjusting P1 CO
2
level
Fig. 70 Adjusting P2 CO
2
level
7.6
Program values
This section describes details on programming the appliance. For most
applications the factory default values will provide robust and stable
operation. Only adjust the factory settings if the installation requires
changes as indicated in the appropriate section of this manual.
Refer to chapter 7.7 Control board diagnostics (page 39) regarding how
to access these P-modes.
CO
2
range (%)
Max. CO level
(measured)
Nat. Gas
max. input
P1
8.3 % - 8.9 %
< 290 ppm
min. input
P2
2.1 % - 2.4 %
< 60 ppm
LP Gas
max. input
P1
9.9 % - 10.5 %
< 290 ppm
min. input
P2
2.5 % - 2.8 %
< 60 ppm
* Values above are for climate controlled conditions. Inputs such
as gas pressure, heating value of the gas, humidity and
temperature of combustion air all impact CO and CO
2
values.
Changes in these inputs can result in different CO and CO
2
values on the same appliance.
Table 33 CO
2
& CO target numbers
+
WARNING:
▶ Misadjusted program values can lead to appliance
malfunction, errors, and service calls.
